Hot-air furnace.



No. 759,235. PATENTED MAY 10, 1904.

P. M. BRUNER. L

HOT AIR FURNACE. APPLICATION FILED JUNE "1, 1901. RENEWED 00113. 1902.

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PAT-EDITED MAY 10, 1904, P. M. BRUNBR. HOT AIR FURNACE. APPLICATIONFILED JUNE7.1901. REHEWED 00T.13, 1902.

3 SHBBTS-8HBET 2- no MODEL.

No. 759,235. PATENTED MAY 10, 1904'.

P. M. BRUNER. HOT AIR FURNACE.

APPLICATION FILED JUNE 7. 1901. RENEWED OUT. 13, 1902.

N0 MODEL.

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Patented May 10, 1904.

UNITED STATES PATENT OFFICE.

PRESTON M. BRUNER, OF LEBANON, ILLINOIS.

HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent N0. 759,235, dated May 10,1904.

pplicati n file June 7, 1901. Renewed October 13, 1902. Serial No.127,187. (No model.)

To (ZZZ whom it may concern:

Be it known that I, PRESTON M. BRUNER, a citizen of the United States,residing at the city of Lebanon, county of St. Clair, State of Illinois,have invented a certain new and useful Improvement in Hot-Air Furnaces,of which the following is a full, clear, and exact description, such aswill enable others skilled in the art to which it appertains to makeanduse the same, reference being had to the accompanying drawings, formingpart of this specification, in which Figure 1 is a side elcvational Viewof my improved hot-air furnace. Fig. 2 is a vertical sectional viewthrough the furnace proper. Fig. 3 is a horizontal sectional view online 3 3, Fig. 2. Fig. 4: is a horizontal sectional view on line 4 4:,Fig. 2. Fig. 5 is a vertical sectional view through the heatingapparatus on line 5 5, Fig. 6. Fig. 6 is a horizontal sectional view.online 6 6, Fig. 5, and Fig. 7 is a horizontal sectional view on line 7 7,Fig. 5.

This invention relates to a new and useful improvement in hot-airfurnaces designed especially for house-heating purposes.

Heretofore furnaces have been provided with mantles into which the heatfrom the furnace radiates, and air admitted to this mantle has beenheated by the said radiated heat. In some instances the furnace properand heating-drum have been arranged horizontally; but in such instancesthe furnace has been of such construction that heat radiates, whereby ithas been necessary to surround both the furnace proper and theheating-drum by a mantle. The combination of a mantle with a furnaceproper presents many objectionable features. It limits the size of thefurnace proper, and therefore limits the gratesurface, makes itnecessary to feed the furnace from the side, thus rendering a largemagazine impossible, necessitates many joints and fittings, presentsgreat liability of gases escaping into the air-space, and in a generalmanner complicates the construction of both the furnace proper and theheating-drum, eachinterfering with the other to prevent an idealconstruction of either.

My object is to overcome the above-mentioned difficulties and to providea furnace of simple construction and great efficiency.

To these ends and also to improve generally upon apparatus of thecharacter indicated my invention consists in the various mattershereinafter described and claimed.

In my construction the furnace proper and the heating-drum are built asindependent structures, and heat is generated in the furnace proper andis carried therefrom to the heating-drum, not wholly or in part byradiation, but entirely by a flue. Preferably the furnace proper is ofsuch construction that no heat radiates therefrom; but all of the heatgenerated is supplied through the flue to the heating-drum. Thus nomantle for the furnace proper is necessary or desirable, and neither thefurnace proper nor the heating-drum interferes with the other, the sizeof the furnace proper being limited not by an inclosing mantle, but onlyby the size of the cellar or other space into which the apparatus is tobe placed.

In the drawings, the furnace proper consists of an inclosing shell orcasing A, the lower part of which is provided with an ashpit door B.

C indicates a casting riveted to the interior of the casing A above theash-pit and forming a support for the grate-bars I) and for the lining Eof the fire-chamber. This lining is perforated or fluted at 0 around itsexterior periphery, so as to permit the passage of air down into the ash-pit. The upper inner edges of these tiles E are recessed or cut away toform when the tiles G are in position an air-chamber F. These tiles Grest at their lower edges upon a shoulder formed on the tiles E and attheir upper edges against the inner edges of tiles H. The tiles H aresupported by the tiles E and G and have their outer edges inclinedupwardly and outwardly, so as to form an encircling air-chamber f, whilegrooves it lead from the coal-reservoir down into the chamber f.

I indicates a coal reservoir or chamber into able manner to the upperend of the shell A. 70 indicates an openingleading from the ex- Theshoulders of the tiles E are inclined opposite these openings, as shown,for preventing coal or ashes from lodging thereon and choking theopening. There are a number of these openings 71;, one being preferablyopposite the exit-fine for the products of combustion, but none beingopposite the intake-opening Zr. The object in this is to force the coldair entering the opening it to travel some distance, and thereby becomeheated before it mingles with the hot gases and products of combustionpassing through the openings in.

It will be noted that the lower portions of the tiles E are thicker atthe back of the furnace than at the front thereof, and this locates thefire-chamber eccentrically with respect to the shell or casing A. By thearrangement of the tiles G in conforming to the eccentrically placedfire chamber the airspace F is smallest at a point where the cold airenters through the opening it and largest where the products ofcombustion pass into the exit-flue L. The cold air is thus given anopportunity to expand while it is being heated by contact with the hottiles and upon commingling with the volatile gases entering theair-space F supply oxygen to produce complete combustion of saidvolatile gases, and the mixed air and gases in this highly-heated state,almost in the form of a flame, are admitted into the exit-flue L. Ofcourse there are products of combustion resulting from the burning fuel111 the lower part of the firechamber which also pass into the fiue L;but these serve to intensify the heat of the commingled air and volatilegases. Thus in addition to forming a conduit for such products ofcombustion as may be received thereby the chamber F also forms aneffective mixingchamber for the volatile products from the fuel and thefresh air to support combustion thereof entering through the opening is.

In operation after the furnace is started coal is introduced into thereservoir, preferably filling the same, and if it is desired to obtain ahot fire on the grate the ash-pit door is opened, so as to permit of astrong draft upwardly through the fire-chamber and into the flue. Afterthe fire is well under way the draft through the ash-pit door ispartially shut off and the opening 71:, made available, which results inadmitting fresh air into the mixing-chamber. As the direct draft is notabove the line of the openings in, it follows that the burning fuel willbe confined in the fire-chamber below said openings, and as said fuel isexhausted and turned to ashes the green fuel in the reservoir abovefalls by gravity, so that the fire-chamber is kept well supplied at alltimes.

I have spoken of the burning fuel being below the line of the openingsis. I will state, however, that the radiated heat from this burning fuelevaporates the volatile gases from the green fuel immediately above theline of openings 7c, and in the event that the cover is closed, whichcover is preferably airtight, these volatile gases will when they havean opportunity escape through the open ings k in a highly-heated stateand then be commingled with the heated air which has entered through theopening Z3. I prefer in some operations of the furnace to leave thecover before referred to tilted, so as to admit a small quantity of air.on top of the bed of green fuel in the reservoir. Of course a largequantity of this air will ascend through the fire-chamber and create adraft which will carry with it the volatile products from the fuel,causing them to pass through the openings 1;. Part of the air enteringfrom above will pass through the grooves h and into the chamberf andthen down through the grooves e. In this manner a small quantity offresh air is admitted to the ash-pit to support combustion in thefire-chamber. This air also tends to cool the shell Aand the outer facesof the tiling.

By the above operation it will be noticed that, due to radiated heat,the volatile gases are driven off from the green fuel above the line ofopenings it" and that said fuel becomes coked; that in this state it isin the best condition for combustion and will descend, when anopportunity presents itself, to a position below the line of openingsin, where it is capable of being burned, complete combustion thereofresulting; that the furnace in normal operation is seldom run with afull updraft through the fire-chamber, (on the contrary, the draft isaround the fire-chamber in the airspace F, and consequently is only ableto support combustion of that material opposite the openings k;) thatthe radiated heat in coking the green fuel and driving off volatilegases forces said volatile gases which are in close proximity to theopenings L" to at least contact with incandescent fuel, so as to burnthe free carbon, and that the air to support combustion of the volatilegases while admitted at a low temperature is heated before beingcommingled with said Volatile gases and when commingled said gases arethus in the best condition to effect complete combustion of said gasesthe instant that the gases and commingled air are permitted to expandfor the purpose of combustion. The small amount of products ofcombustion resulting from the burning of the coked fuel in the lowerpart of the fire-chamber passes with the commingled air and volatilegases in a highlyheated state into and through the exit-flue L, whichexit-flue leads into the heating apparatus.

The fuel is completely consumed in my improved furnace, free carbon inthe products of combustion being absent and a very small quantity ofashes falling into the ash-pit; but with respect to this a moreimportant point is the entire absence of clinker and unburned coal orcoke in the ash-pit.

The tiles about the lire-pot and the green fuel in the reservoir abovethe same are poor conductors of heat and prevent radiation of heat fromthe furnace proper. Should any heat radiate from the tiles, however, itis taken up by the incoming air flowing downwardly through the passagesit, f, and a and is returned to the fire-pot, whereby the shell of thefurnace proper is kept cool and the heat in the lire-pot is augmented.The prod nets of combustion and allof the heated air are conducted fromthe furnace-proper through the flue L to the heating-drum.

The heating apparatus (shown in Figs. 5 and 6) consists, preferably, ofa cylindrical mantle N, into the bottom of which leads a cold-air duct72., while from the upper portion lead hot-air pipes 02/, said pipesgoing to the various rooms or apartments to be heated. In this shell ormantle is arranged a casing 0, preferably cylindrical, which casing ismounted on a suitable base 0. A flange-ring p is secured to the upperend of easing O and to an inner cylinder P, which cylinder is supportedat its lower end upon the casting 0. The flue L, before referred to,passes through an opening in the mantle N and enters the space betweenthe cylinders O and P, discharging the gases passing therethrough intosaid. space. In order to prevent these hot gases from impinging againstthe cylinder P and also for the purpose of directing said gases upwardlyinto the space between the cylinders O and P. I arrange adeflecting-hood Q, preferably made of fire clay, on the inner end of theflue L, said hood being supported by suitable brackets secured to eitherof the cylinders O or P and discharging gases received by it from theflue L in an upward direction. The tendency of these heated gases is torise in the space between the cylinders O and P. Finding no exit at thetop, as they become cool or as they are induced by a draft they descendinto the base 0, which base is provided with a number of ways orconduits 0, leading to a central chamber, from which rises a cylindricalstack R. This enter the space between the cylinders O and P they aredirected upwardly, and immediately that they issue from the hoodeddeflector they are permitted. to expand and spread in said space. Theproducts of combustion descend when they become cool or when induced todescend by the chimney draft to the passages 0,whence they enter thestack R and pass therethrough and the small pipe r into the chimney. Thecold air to be heated entering pipe 11 may pass upwardly either betweenthe cylinder 0 and the mantle or between the cylinder P and the stack R.In any event it is heated, and when it reaches the upper portion of themantel it is conducted by pipes a to the rooms or apartments to beheated. I will state that an apparatus constructed as above describedhas been in use by me for heating a ten-room house. The fuel used wassoft or bituminous coal, and during the six months time in which thefurnace was in op eration about fifteen to eighteen tons of bituminouscoal were used in my furnace as compared with a corresponding number oftons of hard or anthracite coal which would have been required to heatthe same house if an ordinary upright furnace, such as ordinarilyemployed, had been used.

From the above it will be seen that the furnace being arranged in closeproximity to the heating apparatus enables the heat generated in thefurnace and in the heating-drum in the event that the volatile gasesburn in the drum to be directly taken advantage of, the air absorbingsaid heat readily from the expansive surface of the drum. It will alsobe noted in this regard that the heating-d rum instead of being piercedby a single air-duct, as the cylinder P, can have a plurality of ductsor pipes through which the air can pass.

\Vith regard to the furnace it will be seen that the green fuel in thetop of the reservoir is kept 0001 until it has descended some distancedown into the coking-chamber formed by the tiles (1i. These tiles G forma tapering coking-chamber largest at its lower end, so that when theheavy hydrocarbon gases exude from the fuel being coked, which gases orsemiliquid ingredient will tend to cake the fuel, the divergent walls ofthe chamber facilitate the descent of the fuel and prevent the chan1-her from becoming choked. Of course it is desirable to keep thereservoir filled with fuel at all times and, as has been just abovestated, the fuel has been kept cool in the reservoir and in its naturalstate until it is received by the coking-chamber. In practice a fullreservoir should supply fuel to the furnace for twentyfour hours withoutrenewing the fuel. The thickness of the lower portions of the tiles Eopposite the lire-chamber prevents any amount of heat from radiatingfrom the furnace proper, and the presence of the grooves in the outerfaces of these tiles also permits the air to absorb some of this heatand keep it in the furnace.

It is highly desirable in my present invention that the furnace shallgenerate heat to drive oh the volatile gases, so that not only the fuel,but the gases thereof, shall be completely consumed and that as high apercentage of heat units generated by the fuel be delivered into theheating-drum as is possible. To this end the eXit-flueL is preferablymade of fire-clay having thick walls, so as to prevent the radiation ofheat, and, if desired, can be covered with an asbestos covering orsurrounded by an inclosing shell forming a deadair space, whichexpedients are common in the art.

I am aware of the existence of magazine heating-stoves in which fuel isplaced in a reservoir or chamber in the top of the stove; also, thatheating-drums have been" employed around stovepipes to increase the areaof heating-surface, and so heat the air in a room or apartment.Therefore I do not broadly claim the combination of self-feedingcombustionchamber and a heating-chamber, except in so far as saidheating-chamber, closely connected, is made the recipient of totalinitial heat of fuel consumed and its housing or mantle is apart fromthe combustion-chamber, thus requiring a flue to pass products ofcombustion through the mantle into the heating-drum.

It will be apparent that the present construction presents many materialadvantages over apparatus in which heat is radiated from the furnaceproper in to amantle or heating-drum. he furnace proper is notcomplicated by an encircling mantle, but can be constructed withreference to its use as a combustion apparatus only, thus making itpossible to build the furnace proper in such manner that it producesperfect combustion in the simplest form. All of the heat units are heldin the furnace proper until transmitted to the heating-drum through theflue L. Abundant grate-surface is provided, and the furnace includes alarge magazine which is fed from the top. The heating-drum presents anunusually large radiating-surface in small compass and is of cheapconstruction, involving no intricate parts, but few joints and fittings,and no parts liable to burn out or clog with ashes or soot. Furthermore,the present apparatus avoids all liability of gases from thecombustion-chamber getting into the space for the air to be heated.

I am also aware that many minor changes in the arrangement,construction, and combination of the several parts of my device can bemade and substituted for those herein shown and described without in theleast departing from the nature and principle of my invention.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

1. In a furnace, a shell, and a fire-chamber eccentrically arrangedtherein, there being an air-opening into the narrower portion of thespace between said shell and the wall of said fire-chamber, an openingleading from said fire-chamber to the broader portion of said space, andan exit-flue leading from said broader portion of said space;substantially as described.

2. In a furnace, the combination with the shell, of a lining for thefire-chamber, and tiling arranged above said fire-chamber and forming anencircling air-space of graduallyincreasing area toward. theescape-flue; substantially as described.

3. In a furnace, the combination with the shell, of a lining for thefire-chamber, tiling arranged above said fire-chamber and forming anencircling air-space which communicates at various points with the upperportion of the fire-chamber, an escape-flue leading from said air-space,and an opening for admitting fresh air into said air-space;substantially as described.

4. In a furnace, the combination with the tiling forming thefire-chamber, and a mixingchamber, the lower portion of whichmixingchamber communicates with the upper portion of the fire-chamber,and an escape-flue leading from the mixing-chamber and opposite one ofthe communicating openings between the mixing and fire chambers;substantially as described.

5. In a furnace, the combination with the tiling forming thefire-chamber, of tiling arranged thereabove and forming a passage forthe supply of fuel from a reservoir, said lastmentioned tiling alsoforming a mixing-chamber; substantially as described.

6. In afurnace,the combination Withashell, of tiling lining said shelland forming a firechamber, tiling supported upon said first-mentionedtiling and spaced from said shell, and tiling spanning the space betweensaid secondmentioned tiling and said shell, whereby a chamber is formedbetween said various tilings and the said shell, said first-mentionedand said last-mentioned tilings having grooves in their faces adjacentsaid shell for the circulation of air; substantially as described.

7. In a furnace, the combination with the shell, of tiling E, G and Hforming the firechamber, an air-space which communicates at its lowerportion with the upper portion of the fire-chamber, an opening Ir;leading into the upper portion of the front of said airspace, and anescape-flue leading from the back of said air-space; substantially asdescribed.

8. In a furnace,the combination with a shell, of tiles having theirinner, upper portions cut away to produce a shoulder, tiles supportedupon said shoulder and spaced from the remaining upper, outer portionsof said firstmentioned tiles, and tiles spanning the space between andsupported upon the upper ends of said before-mentioned respective tiles;substantially as described.

9. In a furnace, the combination with a shell having an ash-pit at itslower portion, and a reservoir at its upper portion, of a fire-chamberabove the ash-pit, tiling for forming a mixing-chamber F, whichmixing-chamber communicates with the fire-chamber at different points, aflue leading from the mixingchamber for conducting off the products ofcombustion from the fire-chamber and also the commingled air andvolatile gases from the mixing-chamber, an opening leading from theexterior into the mixing-chamber at a point opposite the exit-flue, thereservoir above the fire-chamber constantly supplying fuel thereto, andducts or passages from said reservoir to the ash-pit beneath thefire-chamber; substantially as described.

10. The combination with a furnace of the character described and itsescape-flue, of a drum consisting of the cylinders O and P, saidescape-flue leading into the space between said cylinders, a hood fordeflecting gases passing through the escape flue upwardly in said spacebetween said cylinders, and an axiallyarranged stack communicating atits lower end with the lower portion of the space be tween the cylindersO and P; substantially as described.

11. The combination with a furnace of the character described and itsescape-flue, of a cylinder O through which said escape-flue passes, adeflecting-hood on the end of said escape-flue, a cylinder P, abase-casting upon which said cylinders are mounted, said basecastingbeing provided with radial passages, and a centrally-arranged stack forconducting off the products of combustion entering thereinto from saidradially arranged passages; substantially as described.

12. The combination with a shell having a reservoir at its upper end andan ash-pit at its lower end, of a lire-chamber, inclined tiles G forminga tapering coking-chamber which connects a reservoir and the [irechamber, said tiles also forming, in part, an encircling mixing-chamber,and openings leading from the junction of the coking and lire chambersinto said mixing-chamber; substantially as described.

13. In a furnace, a fire-pot lining having formed therein a chamber forreceiving the heated gas and products of combustion, said chambersurrounding the fire-pot space, openings leading through the wall ofsaid lining from the lire-pot to said chamber, and an escape-flue fromsaid chamber; substantially as described.

14. In a furnace, a lire-pot, a surrounding chamber for receiving theheated gases and products of combustion, an escape-flue leading fromsaid chamber, and air-passages extending substantially entirely aboutsaid fire-pot and substantially the whole length thereof and having oneend open to atmosphere and the other end leading into said fire-pot tosupply air thereto; substantially as described.

15. In a furnace, a fire-pot with an inclosing wall of material which isa poor eonductor of heat, a magazine above said 'lire-pot, whereby fuelin said magazine can form substantially a continuation of the said wallfor the purpose of preventing escape of heat from said fire-pot, and aflue for the escape of heat; substantially as described.

16. In a furnace, a fire-pot having a wall about the same, anddraft-passages outside of said wall at the exterior of the furnace, saidpassages extending substantially entirely about the furnace forreturning escaping heat; substantially as described.

17. In a furnace, a fire-pot having a wall of material which is a poorconductor of heat, and an air-passage outside of said wall at theexterior of the furnace, said passages extending substantially entirelyabout the furnace for returning escaping heat; substantially asdescribed.

18. In a furnace, a fire-pot having a wall about the same and providedwith a bottom opening for ingress of air, and a draft-passage outside ofsaid wall and leading to said bottom opening, said draft-passage beingopen to the atmosphere at its top; substantially as described.

19. In a furnace, a chamber for the production of heat, and air-passagesoutside of said chamber and extending substantially the whole lengththereof, said passages having one end open to the atmosphere and theother end in communication with said chamber, whereby escaping heat isreturned to the furnace; substantially as described.

20. In a furnace, a fire-pot, a separate magazine supported thereon, anda mantle surrounding said parts and spaced therefrom to produce anair-space; substantially as described.

21. In afurnace, a firepot, aseparate magazine supported upon saidfire-pot, and a mantle aboutsaid parts, there being an air-space betweensaid parts and said mantle and having one end leading to atmosphere andits other end leading to said lire-pot; substantially as described.

22. In a furnace, a fire-pot, an inclosing mantle therefor and having anopening to atmosphere, and an airspace between said mantle and fire-pot,one end of said space leading to said lire-pot and the other end thereofcommunicating with said opening; substantially as described.

23. In a furnace, a lire-pot, an inclosing mantle therefor and having anopening to atleading to said fire-pot and theother end mosphere, anair-space between said mantle thereof communicating with said opening;and fire-pot, one end of said space leading to substantially asdescribed. said fire-pot and the other end thereof com- In testimonywhereof I hereunto affiX my I5 5 municating with said opening, and aclosure signature, in the presence of two witnesses,

for said opening;substantially as described. this 5th day of June, 1901.

24. In a furnace, a fire-pot, a magazine, a

mantle inclosing said fire-pot and having an PRESTON BRUNER" opening toatmosphere which forms a feed WVitnesses:

-for said magazine, and an air-space between V GEORGE BAKEWELL,

said mantle and fire-pot, one end of said space ANNA S. GRAY.

